After spending hours practicing and performing in school and sitting in with whatever bands you can find, you're finally offered a real GIG for REAL MONEY! Definitely not in abundance these days, they mostly consist of small groups with one or two horns, so you'll often be playing as the only wind instrument in the group, maybe as a vocal accompanist. Well, equally as important as your performing ability is your professionalism, which includes, but is not limited to:

Being mentally prepared (free of extraneous influencers), well-rested and well-fed with a cheerful and compliant attitude

Paying attention to the leader and your band mates while performing (cell phone off and out of sight)

Fitting in as part of the ensemble; tailoring your playing to match the venue and event

Returning to the stand promptly after breaks

Interacting cordially with the guests, refraining from negative comments or self-promotion while in someone else's band

Let's face it, gigs for the performing musician are not easy to come by these days. If you want to be asked back, you would do well to observe all the above "no-brainers" as well as your own common sense along with the golden rule. All the talent and performing ability in the world is no substitute for professionalism. NO bandleader wants to babysit or make special allowances for a self-perceived "star." There are just too many to go around.